Exclusion Criteria

1. Preexisting disorder
    a. Genetic or metabolic disorder with CNS involvement
    b. Cardiac disease
    c. Pulmonary disease requiring home oxygen therapy
    d. Known GERD on treatment with a clinical history at presentation consistent with vomiting or reflux
2. Bronchiolitis or pneumonia
    a. Cough and/or congestion at presentation
    b. An abnormal chest radiograph at presentation
3. Unstable vital signs in the emergency department
    a. Hypoxia
    b. Bradycardia
    c. Hypotension
    d. Respiratory failure requiring intubation
    e. Fever with at least 1 of the following: cerebrospinal fluid pleocytosis, abnormal urinalysis, or abnormal complete blood count results
4. Seizure disorder
    a. Known history of seizures
    b. Seizure in the emergency department
    c. History for seizure convincing to the emergency department physician, and age >6 mo
5. CNS pathology
    a. Known history of intracranial or CNS pathology
    b. Ventriculoperitoneal or ventriculoatrial shunt placement
    c. Hydrocephalus
    d. Structural brain abnormalities
6. Previous treatment with antiepileptic drug
    a. Including benzodiazepines administered before hospital admission, either in the emergency department or by paramedics
7. Febrile seizure (seizure associated with fever and age >6 mo)
8. Medication misdose
    a. Known ingestion
    b. Medication overdose
9. Trauma
10. Known child abuse
    a. Imaging results at the time of admission consistent with child abuse